The arrival in San Diego over recent days of Central American families who crossed the border in Texas has prompted questions: What happens next?

After initial processing by U.S. Customs and Border Protection, it is up to another agency, U.S. Customs and Immigration Enforcement, to determine who will be released, and who should remain in custody as their cases undergo review. Many are fleeing violence and poverty, but those factors alone are not sufficient to receive asylum in the United States.

Of those who arrived last week, most are not expected to remain in the San Diego region, but will be sent to stay with friends and family members in other areas while their petitions are considered by asylum officers and immigration judges.

This is the path for many Central Americans seeking refuge in the United States.

Question:What happens when a person is caught entering the country illegally, or walks up and gives himself up to U.S. border authorities?

Answer: If it’s outside a U.S. port of entry, the person is brought to a Border Patrol station for processing. At this initial screening, agents determine the individual’s age and citizenship. They search for any previous immigration record and criminal history. Individuals are asked questions such as how they got to the border, and who they came with. They are photographed and fingerprinted, if over age 14. They undergo medical screening.

Anyone under age 18 traveling without a parent or guardian is classified as an unaccompanied minor. Unaccompanied minors from contiguous countries — Canada and Mexico — are screened to ensure that they are not a human trafficking victim, have no claim to asylum or other forms of relief and voluntarily agree to return home. All other unaccompanied children must be transferred to the custody of U.S. Health and Human Services within 72 hours.

Anyone taken into custody has the right to contact a family member in the United States and their country’s consulate.

Q: After the initial interview, what happens?

A:Many border crossers are quickly sent back to their home countries through voluntary return, expedited removal or reinstatement of removal. Voluntary return, increasingly rare, allows the person to go home voluntarily without a formal order. More commonly used is a process called “expedited removal” in which the Department of Homeland Security may order an individual’s deportation without going through an immigration judge. A third option, “reinstatement of removal” allows someone who has previously been deported to be sent back without review by an immigration judge.

Many of the Central American families are being allowed to remain in the United States as they undergo deportation proceedings, but are expected to maintain contact with immigration authorities.

Q:Who gets detained, and who is released from custody?

A:After CBP’s initial processing, it is up to Immigration and Customs Enforcement (ICE) to determine custody. In some cases, detention is mandatory. But others can qualify for release while their petitions to remain in the United States are under review.

Because of the lack of detention space for families in removal proceedings, they are less likely to be detained than individuals. But other factors can also affect the decision, such as whether individuals have a criminal history, if they are a flight risk, or if they’ve been deported before.